Flora of New Zealand Series

Type: A, Specimen Creek, J. Dall.

Glab. tree with spreading branches, up to 6 m. tall; trunk up to c. 2 dm. diam., bark grey; branchlets rather stout, often subwhorled, bark reddish purple. Lvs us. crowded towards tips of branchlets, alt. to subopp., or whorled, on stout petioles up to 2 cm. long. Lamina coriac., 5-10 × 2.5-3·5 cm., elliptic to elliptic-oblong, acute to acuminate, glab. (sts sparsely hairy when young), sharply and coarsely serrate (occ. lvs are entire to subentire). Umbels terminal, compound, densely aggregated on short peduncles; bracts conspicuous, early dehiscent; fls fragrant. Sepals linear-subulate to acuminate, up to 1 cm. long; petals white, linear-oblong, obtuse, 2 cm. long or slightly more. Capsules aggregated, elliptic-oblong, c. 1 cm. long or more, 2-valved; valves woody, finely granulate; seeds immersed in pulp, long-persistent after fall of valves, ± enclosed by papery endocarp.

DIST.: S. S.W. of Collingwood near Boulder Lake; Specimen Creek and Snow's River; head of Slate River; Cobb Ridge.

FL. 11-1. FT. 1-3, but not exactly known.

For a detailed study of the fr. characters see Moore and Adams in T.R.S.N.Z. 77, 1949, 250-252.

REMARKS

1. General Taxonomy. The genus as a whole is in need of critical revision. There appear to be good grounds for creating subgenera in the N.Z. spp. In particular P. anomalum, P. eugenioides, P. dallii recede considerably from the other spp. Some of the points have been raised by L. B. Moore and N. M. Adams (loc. cit.). Revision should, however, be made in connection with the study of the genus as a whole.

2. Heteroblasty. Some reference has been made in the text to the occurrence of juvenile forms markedly different from those of the adult plants. The matter is discussed in some detail for the small-lvd spp. by Laing and Gourlay in T.R.S.N.Z. 65, 1935, 44-62, but we are still largely groping in the dark and much more work is required to make matter clear. The phenomenon is shown in several spp. not dealt with by Laing and Gourlay, e.g. P. patulum, P. turneri, though here our knowledge is more definite.

3. Sexual Expression. Our knowledge is quite fragmentary and the subject deserves detailed study for each sp. How far the different sexual states are correlated with different developments of the infl. as a whole, and how far the development has been towards complete dioeciousness, for example, remains uncertain. The genetics of differences involved in the variation shown in fl. colour has not been studied, though it is known that several spp. with dark petals show forms with yellow ones.

4. Polymorphy and Hybridism. Here again we are on very uncertain ground. We have little or no exact knowledge of how far the differences found are due to the existence of varieties, how far to hybridism, how far to habitat modifications, how far to "geographic races". We have a number of ill-resolved complex groups, e.g. (a) tenuifolium - colensoi - buchananii - fasciculatum; (b) rigidum - crassicaule - divaricatum; (c) virgatum - matthewsii; (d) pimeleoides - reflexum.

Kirk in T.N.Z.I. 4, 1872, 267 states: "I am informed by Dr. Hooker that several of the New Zealand species produce self-shown hybrid forms freely under cultivation in the south of France." There is good evidence that hybridization does frequently occur among wild plants, but more detailed study is required before its importance in producing the complexes met with can be properly estimated. P. intermedium, as indicated in the text, is possibly of hybrid origin. Cockayne and Allan (Ann. Bot., Lond. 48, 1934, 23), in recording P. colensoi X P. tenuifolium, remarked: "it will take many years of critical garden experiments before this group is well understood. Both colensoi and tenuifolium are complicated linneons." We have hardly advanced on this position as yet. After recording several doubtful hybrid groups they stated that P. pimeleoides when occurring with P. reflexum produces "typical polymorphic hybrid swarms".